Dashpot



C. B. COATES.

DASHPOT.

APPLICATION FILED MAY?. |920.

Patnted Nov.. 2L 1922.

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CHARLES B. COATES, 0F NEW YORK, N. Y., ASSIGNOR T0 CHICAGO PNEUNIATIC TOOL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

DASHPOT.

Application led May *7, 1920. Serial No. 379,460.

To all whom it may concern:

Be it known that I, CHARLES B. CoA'rE's, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Dashpots, 0f which the following is a specification.

My invention relates to dash-pots and the principal object of my invention is to construct a novel, simple, efficient and reliable dash-pot adapted for use in overload circuit breakers and the like. Other features of advantage and utility in my invention will be understood from the description hereinafter given. While I have shown and described the dash-pot, embodying my present invention, as cooperating with a solenoid plunger for controlling the switch of an overload circuit breaker in a novel and eicient manner. it is to be understood that the invention is susceptible of use in connection with other devices and apparatus.

ln the drawings Fig. 1 is a side elevation of my circuit breaker, embodying the dashpot constructed in accordance with my invention hereinafter claimed; Fig. 2 an end elevation thereof viewed from the line 2-2 of Fig. 1 and looking in the direction of the arrow; Fig. 3 a perspective of a detail of the contact base; Fig. 4 a sectional plan of the switch mechanism taken on the irregular line 4-4 of Fig. 5; and Fig. 5 a sectional elevation on the line 5-5 of Fig. 2.

Referring to the particular embodiment of my invention which is herein shown for the purpose of a clear and deinite description but which may partake of different forms, the mechanism is mounted on and supported 'by an angle iron framework 1 carrying a base 41 of insulating material. The mechanism comprises essentially a solenoid and switch mechanism together with a dash-pot arrangement for cont-rolling the movements of the solenoid core or plunger.` This solenoid is preferably of the stopped iron clad type consisting of the casing or frame 2, series coil 3 and core or plunger 4. This solenoid is secured to the brackets 5 which in turn are secured to the frame work 1. The solenoid is also provided with an iron plug 6 which extends into the core opening of the coil and is secured to an end disk or plate 7 in suitable manner as by screwing thereinto. This plug has a central bore in which slides by a nice sliding fit a rod 8 which is made of suitable non-magnetic material such as brass. This rod is unattached at either end. but is adapted to contact at its right hand end the plunger 4 and at its left hand end the dashpot device as hereinafter explained.

The dashpot device is contained within a casing 9 secured in suitable manner to the casing or frame-2 of the solenoid as by screwing thereinto and locked in place by means of set screw 10. Within this case there is located a cylinder 11 which provides a dashpot chamber 12. A portion of the interior of the casing 9 is of larger diameter than the cylinder 11 with the'result that an annular chamber 13 is formed therebetween. This annular space or chamber communicates with the dashpot chamber 12 through the rearward ports 14 and a forward port 15 which is located intermediate the length of the cylinder 11.

Within the cylinder 11 there reciprocates a piston 16 which has a tubular stem 17 adapted to communicate with opposite sides of the piston through the ports and passages 18 and the port 19 passing through a disk 20 in the left hand end of such stem. The ports and passages 18 are governed by means of a check valve within the stem which valve is here a ball 21 spring pressed to its seat by means of the spring 22. This piston is held to the normal position shown in Fig. 5 by means of a yielding pressure such as the coiled spring 23 bearing at its inner end against the piston and at its outer end against the head of an adjustable hollow screw 24 which screws into and through the boss 25 of the casing 9. The rod 8 bears at its outer end against the flat face of the piston 16 and is adapted to force such piston outwardly to the left when actuated by means of the plunger 4 in the manner hereinafter explained.

Referring to the switch controlling mecha nism which is actuated by the plunger 4, the same consists of a bolt 26 secured to the projecting end of the plunger in suitable manner as by screwing thereinto and clamping between the end thereof and a nut 27, a plate 28 whose uper end is notched in order to receive the lower edge of a bracket or guide 29 which is secured to and projects forwardly of the right end of the casing 2. This bracket is provided with a flange 30 or saddles and interposed spring'.

a rial.

thereby enabled to actu ate the switch and its,

operating' means now to be described.

My switch is of .novel construction particularly as to the contacts which here consist ot threerollers on the one side and two seats Two oit these rollers 342 E34 are of the Same diameter but the third roller 35 which is interposed between them 'is of somewhat greater diameter. These rollers are all mounted upon a horizontal rodo' connectingrv the outer ends ot' a yoke or substantially rectangular frame which is composed of two parallel; bell cranks having long arms 3i" andi short up- `right arms 3S. These bell cranks are piv-v oted upon the rod 39 at the upper end otl the standard 40 which is secured to the basey or support 4l. rlhe upper ends oi? the bell crank arms 38 are connected. by the cross rod 42. These rollers and their yoke are held to the normal downward position shown in l? 5 by suitable means such as the spring' 43. i i

These rollers 34 and 35 constitutey switch contacts that are adapted to cooperate with other switch contacts which consist of the saddles 44 cooperating with the smaller rollers S4 and with a spring 45 made of suitable material such as bronze or non-areing mate- This spring is secured at its outer end tothe plate 46 and its :inner end projects for,- wardly between the two saddles 44 in position to be 'contacted by the larger roller The construction and arrangement oi these parts are such that the larger roller docs not leave its contact or spring; 45 until zitter the smaller rollers 84 have left their seats in the saddles 44 with `the result that the current passes through the larger roller and througlrits spring when such current; is linally broken, and is not thenv passing,

through the smaller rollers, so that the seatsv and the other end` to the base40 so that cur-.

rent flows througliuit only when the switch is in the open position. This coilI is mounted` at the upper end of twouprights or standardsv or magnetic yokes 4 8 which a1 esuit,

ably mounted. This coil cooperates with a pair of magnetic poles 49 which, in. turn are adapted to attract and hold an iron armature 50 mounted upon the switch breaker device or frame 37. pair of magnetic, plugs 51 are secured in the brackets 52 which are a part oit the casting containing the saddles 44 and positioned with their are gap in the line ot possible arc between the roller 35 and its spring 45 so` as to blowout any such arc. In this construction these plugs 51 constitute the horns of the .magnet andi vare placed very close to lthe rollerv 35 andi its spring and moreover theyhave-,the same elec-v trical polarity as these parts.` when they are; in contact:7 andthe same as thespring.4 after the circuit ist opened. This. is made possible by usino electrical; insulationl 53;be-, tween the plugs ol` andthe magnet yokes 48. The advantage ofthis construction isnto pro vide a very short air gap through the.y arc and obtain an intense, iield for blowing out such arc. v

Describing acycle of operation of myf circuit breaker and starting: with theparts in their. normal position shown in the drawingsy: when the tool such as an electric drill is. started from a state ofl rest there is a mo.- mentary rush of current farin excess. of' the: safe normal running current-` rllhe sudden and intense inward pull; on the plunger 4; due to the high current passing through; the coil 3 is opposed by the dash. pot. 'lili-,is culi-4 rent is of extremely short duration and the port 15 .is so placed that it isnot uncovered; by the piston 1,6 duringthis rush otstzarting current. After the drill has beelli Staltfdiand is running` `without load the plunger 4; and dashpot 1G assume `the positions shown in the drawings. lllhen the drilh is materially slowed down or stopped as by reason of the stickingotthe drill bit-the working current will increase inthe solenoid with the. result that the plunger willi be moredtothe., lett inl Fig. and: consequently the pistonll will be likewise movedy by reason of( ther interposed rod, 8..r Inasmuch as the chamber4 l2 is a closed one this-movement of thepisv tou will causea oom-pressionot the'aii` toitliev left ot such piston thereby opposing. themoveinent of said plunger.. llllhenj the straight side or. right hand: face,A oft-he piss ton 16 has inovedsuiiiciently tov the left" to, uncover the port l5 the annular chamber- 13- will` act as bypass and thepressureolf-'the air on opposite sides of. the pistonl williA he. equalized whereupon. there will be no .flirt-hen resistance (except that exerted the spring` offered to the movement of. the.` plunger,- and such plunger will then move rapidly or snappily toits full position tothe left,

The plunger 4 inits movement or reciprocation tothe letcarries with it the dog 32-y in whose path. ot movementhis located. the. cross rod 42-which` together with themovablg members of the -switch are rocked to the dotted line position shown in l 1 5, The armature 5() is n .v held magnetically by the poles 49 which is the open switch position. In this opera-tion of the switch the small rollers 34 leave their seats while the larger roller 35 is still in contact with its spring and before it breaks contact with such spring. Moreover, the dog` 32 does not strike the cross rod 42 of the breaker device until the plunger has moved to that point where the dash pot piston has passed. the port l5, that is to say the cushioned movement of the plunger 4 occurs before the dog comes into contact with the rod 42 and the cushioning' action is relieved at the moment when such dog makes such Contact with the rod with the result that the rollers are moved out of contact with their contacts rapidly and with a rapid, snappy action. After the current has thus been interrupted or cut out the spring 23 will return the piston and the plunger.

In the solenoid an iron clad magnet is preferably employed so that when the current iiows through the coil there is magnetic attraction between the adjacent ends of the plunger 4 and the plug 6 and also between the ends of the casing 2 and the plate 28.

A divisional application, which was tiled March 14, 1921 and bears Serial No. 452,162, contains claims drawn to the novel features of the arc extinguisher above described, and a second divisional application, which"V was led March 14, 1921 and bears Serial No. 452,163, contains claims drawn to the patentable subject-matter incorporated in the switch mechanism above described.

l claim:

1. In a dash-pot, the combination of a cylinder providing a piston chamber, a piston reciprocable therein, means controlled by the piston for equalizing the pressure on opposite sides of the piston, after a partial transverse thereof in one direction from one position, and means for relieving the pressure on one side of the piston during partial transverse in the opposite direction to said position.

2. ln a dash--pot, the combination of a cylinder providing a piston chamber having a ley-pass connecting opposite ends thereof, a piston reciprocable in the chamber anc normally closing said by-pass but opening the same when reciprocated, and means for relieving the pressure on one side of the piston as the lat-ter moves to normal position and closes said by-pass.

3. In a dash-pot, the combination of a cylinder providing a piston chamber havng a by-pass connecting opposite ends thereof, a piston reciprocable in the chamber and normally closing said by-pass but opening the same when reciprocated, and a check valve passage through said piston.

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4. ln a dashvpot, the combination of a cylinder providing a piston chamber having aby-pass connecting opposite ends thereof, a piston reciprocable in tl e chamber and normally closii'ig said by-pass but opening the same when reciprocated, said by-pass including two communicating ports in the cylinder, the first one at the end thereof and the second one towards the inner end thereof but spaced from such end in position to be normally closed. by said piston, and a check valve in said piston for relieving the pressure on the inner side of the piston as the latter moves to normal position after closinf said by-pass.

5. n a dash-pot, the combination of a cylinder providing a piston chamber, a piston reciprocable therein, means controlled by the piston for equalizing the pressure on opposite sides of the piston, after a partial transverse thereof in one direction from one position, means for relieving the pressure on one side of the piston during movement of the piston in the opposite direction to such position, and a spring for moving said piston in said last mentioned direction.

6.111 a dash-pot, the combination of a cylinder providing a piston chamber, a piston reciprocable therein, means controlled by the piston for equalizing the pressure on opposite sides of the piston, after a partial transverse thereof in one direction from one position, means for relieving the pressure on one side of the piston during movement of the piston in the opposite direction to such position, a spring within said cylinder for moving said piston in said last mentioned direct-ion, and a device projecting through said cylinder and adjustable to tension said spring as desired.

lin a dash-pot, the combination of a cylinder providing a piston chamber, piston reciprooable therein, means controlled by the piston for equalizing the pressure on opposite sides of the piston, after a partial transverse thereof, in one direction from normal position, a stem on said piston, a check valve in said stem, and a coiled spring encircling said stem to move the piston to .normal position.

8, ln a dash-pot, the combination of a cylindrical casng, a cylinder therein providing a piston Jchamber and an annular space between the casing and cylinder and hai/ing ports communicating with said annular space, a piston reciprocable in said chambe and normally closing one of said ports and adapted to uncover the same after a movement of said piston from normal position to equalize the pressure on opposite sides of the piston during further movement of the piston.

9. ln a. dash-pot, the combination of a cylindrical casing having ends, a cylinder therein providing a piston chamber and an ment 01'. the piston from normal to equalize the pressure on opposte sides of the piston movement of the pieton;A and a, check Valve for relieving the p-essnne during Continued on one side of th e piston as the latteri's moved to normal position.

ARLES B. ooATESj 

